DISCOVER

## Video transcription

Hi I'm Steve Jones and I'm going to explain how an electric circuit works. Well first of all we have to remember that there are certain things which conduct electricity which we call conductors and there are others which don't conduct which are called insulators. Now conductors and insulators you must know the difference between the two. A conductor is something which allows the current to pass through it so an electric circuit works by connecting things together so that the electricity can pass through it and therefore we must have conducting materials conductors to take the current from one place to another. Typical conductors are copper which everybody knows about and for example aluminum although there are many other conducting materials these are the best two and the ones that are the most used. Insulators are typically things like plastics and glass is also an insulator and in fact many things although we talk about conductors and insulators many things are half way between the two and some partly conduct better than others. One of the best conductors of course is silver actually is a metal so in our circuit, this is a circuit and this is a representation of a circuit but in our circuit to make electric current flow you have to have a supply of power, a power supply. A power supply is the thing which gives energy to the electric current. The electric current is a flow of electrons. It is a flow of little particles called electrons which are negatively charged and these flow around the circuit and you'll see on the power supply a plus and a minus sign. Sometimes the power supply is ac and an ac supply is like that. This doesn't have a plus and a minus in fact the current goes backwards and forwards instead of going continuously round. The power supply is then connected to one side of the machine and from the other side of the machine can go back to the power supply. But in this what we do is we put a switch and a switch is just a simple device. It can simply be that the two pieces of wire are attached together and then separated. You break the circuit by separating these two pieces of wire so here we have got basically the components in an electrical circuit. You have a machine. The machine could be a lamp. It could be a heater. It could be a lot of things. It could be your radio. It could be your television. It could be anything of these, your computer but lamps and heaters, these are types of machines. A machine is just a thing that uses energy so we have the supply of power. We have the machine that needs the power to work and in it we usually include a switch so that we can control when it is on or off. So in this way now we know exactly how an electric circuit works.